The tragic incident occurred shortly before 9pm on Wednesday afternoon on the Costa de la Calma.

It has emerged that Jonathan Hutch (37) - a nephew of Gerry 'The Monk' Hutch - told detectives in the immediate aftermath of the killing that he was the intended target.

However, despite this he is not considered a serious criminal and gardaí believe he was targeted solely because he is a member of the Hutch family.

Mr O'Neill had been walking with Jonathan Hutch alongside a large group at the time of the shooting, but the two men had only recently met each other.

Gardaí believe that members of the Kinahan cartel received information that Jonathan Hutch intended to travel to the Balearic island long before he actually arrived.

Authorities are now examining flight manifests to determine if any known criminals arrived through Palma de Majorca Airport in the days before the fatal shooting.

Spanish police are also investigating whether two burnt-out cars were used as getaway vehicles by the killer and his suspected accomplices.

Locals said the two vehicles - a Volkswagen Golf and a car thought to be a Seat Ibiza - were set on fire simultaneously shortly after Mr O'Neill was gunned down in front of his partner and three children.

Neighbours of the Dublin City Council worker described him as an "absolute gentleman", with the council's chief executive officer saying he was a "hard-working" and "dedicated employee".

Locals left floral tributes at the family home of Mr O'Neill, as a Dublin GAA flag was placed on the gate of the Drimnagh home.

Mr O'Neill's devastated partner Suzanne and their three children were flown home from Majorca and arrived home in Dublin shortly before midnight on Thursday.

They did not return to their family home in Drimnagh yesterday, and are believed to be staying with close relatives in the capital as they come to terms with the senseless killing.

Last night, neighbours of the family said the community was still reeling.

"It's tragic, he was a lovely man and he was a very good dad ... we are heartbroken," neighbour Meriline Calou said.

Jonathan Hutch was on board the same return flight as the O'Neill family. Hutch was escorted through Dublin Airport, with armed gardai guiding him through a private exit, after flight FR9998 touched down.

It is believed that he he has since gone to ground amid fears he may be targeted again by the Kinahan cartel.

It is also being investigating whether the suspected gunman lay in wait for days before the botched gun attack which resulted in the father's death on Wednesday night.

Liaising with their Spanish counterparts, gardaí are probing whether the gunman hid in the Balearic island or mainland Spain for a number of days, intent on murdering Jonathan Hutch - the older brother of feud murder victim Gareth Hutch.

It is believed the killer flew from the UK - where he has been hiding after threats were made against him in Dublin - and made his way to Majorca with the latest feud hit in mind.

The heartbroken family of Trevor O'Neill returned to Dublin shortly before midnight on Thursday, with Jonathan Hutch boarding the same plane home.

Meanwhile, TDs have called on Tánaiste Frances Fitzgerald to inform Spanish authorities that a more robust response is needed to deal with Irish gangs in the southern European country.

Fianna Fáil Justice spokesman Jim O'Callaghan said: "It is astonishing that such a large criminal enterprise can be operated openly from Spain without the intervention of the Spanish authorities. The murder of Trevor O'Neill must result in a more aggressive response from the Spanish authorities."